La Source is a blend of grape varieties, mainly Pinot Noir and Chardonnay, with proportions varying depending on the vintage but often around 50/50. The grapes come from several plots on the estate located in the Côte des Bar region, including Val Ligé, La Fontaine du Noyers and L'Envers-Vigne, on clay-limestone soils typical of the region.

The vinification follows a ‘natural’ and minimally interventionist approach: fermentation and ageing take place partly in oak barrels to add complexity, with the rest in stainless steel vats, ageing on lees for at least 24 months before disgorging. The wine is marketed as Brut Nature, without dosage. The estate is cultivated organically, reflecting a commitment to respecting the terroir and preserving the purity of the fruit.